Some varieties of Tulip do not "perennialize" very well, and either slowly reduce in numbers, or suddenly barely grow. Same with a few varieties of Daffodil.
A couple ways out of it; Plant a different but similar variety. Problem with that is of course, usually the reason for that variety's existence is it is something special.
The other thing you can do is grow that variety, but "primo grow" it. Super good and nutrient rich soil, usually with lots of Phosphorus, a touch more Nitrogen than normal for bulbs, and some Potassium. That'd be about 50 50 compost and soil very deep, double or triple dosed with Bone Meal, single dosed with Kelp, and water it with fish emulsion. Ensure no other plants compete with the unvigorous variety, and continue fertilizing with the fish emulsion, lightening up as the leaves dry. Do not pull the dry leaves off until September. Ensure it gets lots of light.
Also, if you live where there may not be enough hours of freeze for some Daffodils or some Tulips, best thing would get a variety better for the south...